Motor vehicles have fuel piping systems for the supply of fuel from a fuel tank to an engine mounted in an engine compartment. For example, a conventional fuel piping system is shown in FIG. 7, in which numeral 102 denotes a vehicle, 104 denotes a frame, 106 a side member of the frame, and 108 a cross member of the frame. One side member 106 is disposed on each side of the vehicle in the longitudinal direction thereof. The sidewardly spaced side members 106 are connected together by the transversely-extending cross member 108 which is disposed below an engine compartment 110 and is located at the front of the vehicle in the longitudinal direction thereof. In FIG. 7 there is illustrated a single side member 106 located on one side of the vehicle.
In the engine compartment 110 there is mounted a conventional engine 112 aligned in the vehicular longitudinal direction. In the engine 112, as shown in FIGS. 5 and 6, cylinder banks 114A and 114B are disposed in a V shape, exhaust manifolds 116A and 116B as components of an exhaust system are disposed on both sides in the transverse direction, and in a transversely-extending middle region are disposed, as components of a fuel system, delivery pipes 118A and 118B in a right and left relation to each other, fuel injection valves 120A and 120B also in a right and left relation, and a fuel pressure regulating valve 122.
As shown in FIG. 7, the vehicle 102 has a fuel tank 124 mounted on the rear side in the vehicular longitudinal direction. The fuel tank 124 is provided with a fuel pump 126. The engine 112 is connected to the fuel tank 124 through a conventional fuel piping system 128. The fuel piping system 128 for the engine 112 connects the fuel pump 126 to the delivery pipes 118A and 118B through a tank-side fuel supply hose 130, a fuel supply pipe 132 and an engine-side fuel supply hose 134. A fuel filter 136 in the middle of the tank-side fuel supply hose 126 is disposed.
The fuel piping system 128 connects the fuel pressure regulating valve 122 to the fuel tank 124 through an engine-side fuel return hose 138, a fuel return pipe 140 and a tank-side fuel return hose 142.
The fuel piping system 128, including the engine-side fuel supply hose 134 and fuel-return hose 138, which are located in close proximity to the engine 112, are disposed to extend from the front toward the back of engine 112 while detouring above exhaust manifold 116A (FIG. 5), or alternatively are disposed on the rear side of the manifold 116A (FIG. 6).
Such a fuel piping system in an engine is disclosed, for example, in Japanese Patent Laid Open No. 8-334032. According to the fuel piping system disclosed therein, a fuel damper is disposed near the front end of a cylinder bank of a V-type internal combustion engine mounted longitudinally on a vehicle and between the cylinder bank and the inner wall of an engine compartment, and a fuel piping connected from the fuel tank to the fuel damper is disposed to the front side while detouring above the exhaust manifold.
In a conventional arrangement wherein an in-line type engine extends longitudinally of the vehicle, intake components such as an intake manifold are disposed on one side of the engine in the transverse direction, while exhaust components such as an exhaust manifold are disposed on the other side of the engine in the transverse direction. In a fuel piping structure of such a longitudinally-oriented engine, fuel piping is laid on the side of the engine opposite to the side where exhaust components are disposed to protect the fuel piping from the exhaust heat.
In a conventional V-type longitudinally-oriented engine 112, however, intake components are disposed in the middle of the engine (i.e., between the cylinder banks) and exhaust components are disposed on both outer sides of the engine in the transverse direction. In such a V-type engine, therefore, the fuel piping structure 128 is conventionally disposed on the front side of the engine while detouring above the exhaust manifold 116A as shown in FIG. 5, or is disposed on the rear side of the manifold 116A as shown in FIG. 6.
In this case, to protect the fuel piping structure 128 from the heat of the exhaust manifold 116A, it is necessary to provide a sufficient clearance from the exhaust manifold 116A and to cover the fuel piping with a shield member such as a heat protector (not shown). In such a fuel piping structure, however, due to limited space in the engine compartment 110, it is sometimes difficult to provide a sufficient clearance as mentioned above, and using a heat protector increases the number of parts and the number of mounting steps, which causes an increase in the cost of the vehicle.